Conventional servovalves convert relatively low power electrical control input signals into a flow rate or control pressure. For example, during operation pressurized fluid enters the direct drive servovalve and, based upon the control input signals, drives a fluid actuator to operate variable-geometry elements such as associated with an aircraft.
A typical servovalve includes a housing, a valve member such as a spool, and a torque motor. The housing defines a fluid pathway with the valve member being disposed within the fluid pathway. The torque motor is configured to either cause the valve member to move within the fluid pathway in order to control an amount of fluid flow within the pathway or to control a fluid pressure within the fluid pathway.
During operation, a user activates a user input device that generates and delivers a command signal to the servovalve. The torque motor receives the command signal and converts the signal to an output torque where the torque is proportional in magnitude to the command signal. In the case where the servovalve is configured as a direct drive servovalve, the torque motor moves the valve member to a desired position within the fluid pathway to control an amount of fluid flow relative to the fluid actuator. In the case where the servovalve is configured as an electro-hydraulic servovalve, such as a dual nozzle/flapper servovalve, the torque motor positions a flapper relative to a nozzle to adjust a fluid pressure within the housing, which, in turn moves the valve member to a desired position within the fluid pathway